Refrigerant compressor



Jan. 2, 1962 J. M. WELLBORN ETAL 3,01

REFRIGERANT COMPRESSOR Filed April 6, 1959 5 Sheets-Sheet 1 l6INVENTORS.

JohmjL iZflelZom BY John/(21% zimw, 7 y

Jan. 2, 1962 J, M. WELLBORN ETAL 3,015,222

REFRIGERANT COMPRESSOR 5 Sheets-Sheet 2 Filed April 6, 1959 INVENTORS.

f zgngflgellbam 0 Jan. 2, 1962 M. WELLBORN ETAL 3,015,222

REFRIGERANT COMPRESSOR Filed April 6, 1959 5 Sheets-Sheet 3 INVENTORS.

Jan. 2, 1962 J. M. WELLBORN ETAL 3,015,222

REFRIGERANT COMPRESSOR INVENTORS.

7 J3 knMZZ/ellfio 772 BY Jbhn @Kz'mm,

Unite 3,015,222 Patented Jan. 2, 1962 3,015,222 EFRIGERANT CGEIPRESSDR.iohn M. Wellharn and .lohn A. Kimrn, Evansville, Ind, assignors toWhirlpool Corporation, a corporation of Delaware Filed Apr. 6, 1959,Ser. No. 304,174 2 Claims. (El. 230-139) This invention relates tocompressors and in particular to compressors as may be used inrefrigeration systems.

In one form of conventional refrigeration system, a motor operatedcompressor receives gaseous refrigerant under a low pressure from thecooling evaporator, compresses the gaseous refrigerant, and delivers itto a condenser wherein it is cooled to the liquid state, in which liquidstate the refrigerant is delivered to the evaporator wherein itevaporates to effect the desired cooling operation of the refrigerationsystem. To permit the compressed refrigerant to effect a desirablecooling of the motorcompressor prior to its delivery to the condenser, aprecooler may be provided through which the compressed refrigerant maybe passed from the motor-compressor and redelivered thereto prior to itsdelivery to the condenser.

The principal feature of this invention is the provision of a new andimproved compressor for use in a refrigeration system.

Another feature of the invention is the provision of such a compressorhaving an operably associated motor and new and improved means forsupporting and enclosing the motor-compressor combination.

A further feature of the invention is the provision of such amotor-compressor having new and improved means for cooling bearing meansthereof.

Still another feature of the invention is the provision of such amotor-compressor having new and improved means for mufiling pulsationsof the refrigerant flow.

A still further feature of the invention is the provision of such amotor-compressor having new and improved means for removing heattherefrom during a compressing operation.

A yet further feature is the provision of such a motorcompressor whereina portion of the lubricating oil is arranged to effect such heatremoval.

Other features and advantages of the invention will be apparent from thefollowing description, taken in connection with the accompanyingdrawings wherein:

FIGURE 1 is a diagrammatic view of a refrigeration system having amotor-compressor embodying the invention.

FIGURE 2 is a vertical elevation of the motor-cornpressor, the housingthereof being shown in diametric section.

FIGURE 3 is a transverse section thereof taken sub.- stantially alongthe line 3-3 of FIGURE 2.

FIGURE 4 is an enlarged plan view of the compressor portion thereof, thesuperposed motor portion thereof being outlined in broken lines.

FIGURE 5 is an enlarged, fragmentary vertical section of themotor-compressor taken substantially along line 5-5 of FIGURE 4.

FIGURE 6 is a vertical section of the compressor portion thereof takensubstantially along line 6-6 of FIG- URE 4.

FIGURE 7 is a transverse section taken substantially along the line 7-7of FIGURE 6.

FIGURE 8 is a transverse section taken substantially along the line 8-8of FIGURE 6.

FIGURE 9 is a transverse section taken substantially along the line 9-9of FIGURE 6.

FIGURE 10 is a fragmentary, enlarged vertical section takensubstantially along the line 10-10 of FIGURE 7.

FIGURE 11 is an exploded, upwardly looking isometric view of thecompressor portion.

FIGURE 12 is an exploded, downwardly looking isometric view of thecompressor portion.

In the exemplary embodiment of the invention, as disclosed in thedrawings, a motor-compressor generally designated 10 receives hot, lowpressure refrigerant from an evaporator 11, compresses the refrigerantand delivers it to a condenser 12 wherein the refrigerant is cooled andliquified. From the condenser 12, the liquid refrigerant passes througha capillary tube 13 wherein the pressure of the liquid is reduced tolower the temperature thereof. The cold liquid refrigerant is thendelivered to the evaporator wherein it vaporizes to effect the desiredrefrigerating functioning of the sytsem.

To improve the efficiency of the motor-compressor 10, a precooler 14 isassociated therewith to pre-cool the compressed refrigerant prior to itsdelivery to condenser 12. As will be brought out in greater detailsubsequently, the motor-compressor is arranged to utilize the pre-cooledrefrigerant, prior to its delivery to condenser 12, to cool themotor-compressor.

Referring now more specifically to FIGURES l, 2 and 5, motor-compressor10 comprises a motor portion generally designated 15, a compressorportion generally designated 16, and a housing generally designated 17.Housing 17 comprises an upwardly opening, cup-shaped lower member 18 anda corresponding downwardly opening, cup-shaped upper member 19, each ofwhich may be formed as by stamping. The lower edge 20 of upper housingmember 19 is radially enlarged to have an inside diameter slightlygreater than the outside diameter of the lower housing member 18 andpermit a telescopic mounting of edge 20 over the upper end of lowerhousing member 18. The housing is hermetically sealed by seam welding,at 20, lower edge 20 to lower housing member 18 subsequent to the propermounting of motor 15 and compressor 16 therein.

Motor 15 and compressor 16 are solely supported with in housing 17 on amounting plate 21. The mounting plate is provided with three dependingand laterally extending legs 22 which are secured to the bottom 23 ofthe lower housing member 18 by projection welds 24 to space a circularmid-portion 25 of the mounting plate above the inner surface of bottom23. As best seen in FIGURES 3 and 5, mid-portion 25 of the mountingplate is provided with a pair of diametrically related holes 26. A not27 is secured to the underside of mid-portion 25 in coaxial alignmentwith each hole 26 for cooperation with an elongated bolt 28 for securingthe compressor 16 to the mounting plate. The mid-portion 25 of themounting plate is further provided with a second pair of diametricallyopposed holes 29 diametrically related substantially at right angles tothe holes 26, and a central, downwardly extruded hole 30 which providesrigidity to the center of mid-portion 25' and permits circulation oflubricating oil downwardly through the mounting plate.

As best seen in FIGURES 2, 5, 6, ll and 12, compressor 16 includes fourgenerally cylindrical members, including a cover-plate 31, a rear head32, a cylinder 33, and a front head 34. Within cylinder 33 is a rotarypump 35 which effects desired compression of the refrigerant gas.

The coverpiate 31, rear head 3-2, cylinder 3-3, and front head 34 areretained in stacked association by three sets of threaded members. Morespecifically, a pair of short screws 36 extends through counterboredholes 3 7 in cylinder 33 and are threaded into aligned threaded holes 38in front head 34 to secure cylinder 33 in underlying juxtaposedrelationship with front head 34. Coverplate 31 and rear head 32 aresecured to the assembled cylinder 36 and front head 34 by means of longscrews 39 3 which extend upwardly through aligned holes in coverplate31, holes 41 in rear head 32, holes 42 in cylinder 33, and threadedholes 43 in front head 34. The heads of screws 39 are freely received inholes 29 of the mounting plate 21 to permit coverplate 31 to be faciallyjuxtaposed to the upper surface of the mounting plate. The assembledcoverplate, rear head, cylinder and front head are secured to themounting plate 21 by the bolts 28 which extend downwardly throughaligned counterbored holes 144 in front head 34, holes 145 in cylinder33, holes 146 in rear head 32, holes 147 in cover-plate 31, and holes 26in mounting plate 21, to have threaded engagement with the nuts 27secured to the underside of the mounting plate. Thus, cylinder 33 andfront head 34 may be subassentbled by means of screws 36, thesubassembly of cylinder 33 and front head 34 may be subassernbled withrear head 32 and coverplate 31 by means of screws 3?, and the assemblyof coverplate 31, rear head 32, cylinder 33 and front head 34 may besecured to the mounting plate 21 by means of bolts 28. Proper alignmentbetween cylinder 33 and front head 34 is provided by means of analignment pin 13-6 mounted in hole 137 in cylinder 33 and hole 138 infront head 34.

Low pressure refrigerant gas enters compressor 16 through a suctioninlet 45, is compressed in the cornpressor, passes therefrom through afirst outlet 46 to the pre-cooler 14 where it is cooled and partiallycondensed, and returns to the compressor from precooler 14 through asecond inlet 47. The compressed, pre-cooled refrigerant passes from themotor-compressor through an outlet 48 to the condenser 12. Each of theinlets and outlets 4 5 through 48 is sealed to the housing 17 where itpasses therethrough to maintain the hermetically sealed enclosure of themotor-compressor.

As best seen in FIGURE 6, the refrigerant gas passes from inlet throughan elongated filter screen 4 3 into a passage 50 within rear head 32.The inner end 51 of passage 50 extends upwardly to open through a recess52 in the upper surface 53 of the rear head 32. A check valve 54 isseated in recess 52 to preclude reverse flow of refrigerant gas throughpassage 50. A pair of diametrically opposed shallow circular recesses 55overlap recess 52 and an elongated shallow slot 56 extends laterallyacross surface '53 from one of the recesses 55. As best seen in FIGURE6, cylinder 33 is provided with a hole 57 aligned with passage end 51and having a radially enlarged lower portion 58 in which is received acheck valve ball '59 riding on top of the check valve 54 and free tomove a limited distance vertically within hole 57. In front head 34,directly above hole 57, is a chamber 60 which radially inwardly overlapsa central cylindrical chamber 61 of cylinder 33 in which the rotary pumpis disposed.

Thus, the low pressure refrigerant gas may flow from inlet 45 throughpassage'Stl past check valve 54, through hole 57, and through chamber 60into the pumping chamber 61. To preclude surging of the gas as it isdelivered to chamber 61, a number of chambers is associated with thesedelivery passages to chamber 61. More specifically, the surge precludingchambers include the recesses 52 and 55 which are associated withpassage end 51 and slot 56 which extends from one of the passages 55.The distal end of slot 56 underlies a hole 62 in cylinder 33 whichcommunicates with a pair of downwardly opening chambers 63 and 64 inupper head 34. Chamber 63 communicates with chamber 60 through adownwardly opening shallow slot 65 in the lower surface 66 of upper head34. Also communicating between recesses 55 and chamber 60 is a pair ofholes 67 extending through cylinder 33 adjacent hole 57. Thus, thesevarious chambers provide an important unloading function in the startingof the compressor. During the first few rotations of the pump 35 thevalve 54 is held closed by the balance-out pressure established withinthe chambers during the preceding off cycle. This provides asubstantially higher back pressure which allows for easier startingbecause of the reduced load on the motor. After the first few rotations,the higher pres sure gas has been swept out of the chambers and valve 54opens.

As best seen in FEGURES l, 6, 7, 8 and 12, pump 35' comprises a rotor 68carried on the inner end of a shaft 69 which is journalled in a bore 132in a hub portion 76 of front head 34. Pump chamber 61 is eccentricallyrelated to the axis of shaft 69 so that the annular space 7i between therotor and the wall of chamber 61 varies substantially in width, as bestseen in FIGURE 6. Rotor 6-8 is provided with a pair of diametricallyopposed radially outwardly opening slots 72 in which a pair of blades 73is slidably received. As the rotor 68 turns, blades 73 are urgedoutwardly by the centrifugal force and by oil and gas pressure intocontact with the wall of chamber 51. Due to the eccentric relationshipof the rotor and chamber wall, the refrigerant gas which enters annularspace 71 in a large width portion 13-3 thereof communicating withchamber 66 is compressed between the blades 73 as the rotor rotates todispose this gas in an opposite narrow width portion 13-4 of the annularspace (approximately 180).

The compressed refrigerant gas leaves space portion 134 of pump chamber61 through a pair of small, radially extending holes 74 openingoutwardly through a chordal surface 75 of cylinder 33. In thesegmentally cylindrical space 76, extending outwardly from surface 75,is provided a discharge valve 77 controlling the holes 74, a muffler 78which defines with surface 75 a muffler chamber 79 outwardly of valve77, and an arcuate enclosure member 80.

Discharge valve 77 comprises a bifurcated stamping releasably coveringthe outer ends of holes 74 to preclude gas flow from chamber 79backwardly through holes 74. Muffler 78 comprises a sheet metal stampingand is se cured to cylinder 33 by suitable means such as a screw 81which also extends through discharge valve 77 to secure the dischargevalve to the cylinder. Enclosure member preferably comprises a castingsecured to the cylinder 33 by a suitable means such as screws 82 and hasits upper surface 83, lower surface 84 and end surfaces 85 machined tohave substantial sealing engagement with front head surface 66, rearhead surface 53 and cylinder chordal surface 75, respectively, to definean enclosed space 135.

The high pressure gas discharged from holes 74 passes through chamber 79and enclosed space 135 wherein it is mufiied, and from space 135 throughfour small holes 86 into a downward opening chamber 8'7 in rear head32-. From chamber 87 the compressed gas flows through a pair of shallowSlots 88 to a second downwardly opening chamber 89 in the rear head.From chamber 89, the gas flows through a restricted passage 90 to athird downwardly opening chamber 91 and then outwardly from rear head 32through an L-shaped passage including a small vertical hole 92 and alarger horizontally extending hole 93 from which the pro-cooler outlet46'extends.

The purpose of the successive holes, chambers and slots between thepump'chamber 61 and the pre-cooler outlet 46 is to smooth out thepulsations in the compressed refrigerant gas. A first smoothing effectis obtained in the chamber 73 defined by the mufiier 78. A furthersmoothing effect is obtained in the four holes 86 which preferably havea cumulative area of approximately 75% of the cumulative area of the twodischarge holes 74. In addition, the provision of a plurality of holes74 and S6 permits each hole to have a relatively small diameter and longperipheral length thereby further smoothing the gas pulsations. Furthersmoothing of the gas flow is effected by permitting it to expand fromthe four small holes 86 into the relatively large chamber 87. Arestriction of the gas flow passage is then effected by the slots 88which are sumulatively preferably approximately 80% of the cumulativearea of holes 86. The flow of refrigerant gas from chamber 89 to chamber91 is substantially unrestricted by the relatively large passage 90 butflow is again restricted by the relatively small cross section holes 92and 93. Chamber 91 is formed very shallow at the point where hole 92connects to provide an oil scavanging action. Thus, oil is always sweptthrough and out of the chambers 87, 89 and 91, and an oil level is notaccumulated any deeper than the depth of chamber 91.

As discussed briefly above, the pre-cooled refrigerant gas re-entersmotor-compressor through inlet 47. As best seen in FIGURES 6 and 12,inlet 47 is connected to front head 34 in communication with a passage94 which opens at its inner end 95 upwardly through hub portion 71 ofthe front head. In discharging from the passage portion, 95, thepre-cooled refrigerant gas cools the hub 7 9 which serves as the bearingfor shaft 69 and also cools the motor portion of the motor-compressor inpassing from passage portion to outlet 48 in the upper end of thehousing 17. This cooling of the bearing and motor substantiallyincreases the efficiency of the motor-compressor permitting it to besmall in size while yet assuring extended trouble-free operation.

The instant invention further comprehends a novel utilization of thelubricating oil of the motor-compressor to effect a further coolingthereof. As seen in FIGURE 2, lower housing member 18 is filled with abody of suitable lubricating oil 96 to a level at approximately thevertical mid-portion of cylinder 33. As the high pressure refrigerantfluid is discharged into housing 17 from passage portion 95, theinterior of the housing is under a sub stantial pressure. Thissubstantial pressure forces the oil upwardly through hole 31 in themid-portion 25 of the mounting plate 21, through a superposed alignedhole 97 in coverplate 31, and through a stepped bore 98 in rear head 32to chamber 61 of cylinder 33 wherein both low pressure and high pressureconditions prevail. Rotor 68 is provided with a downwardly openingrecess 99 overlying and communicating with bore 98, and a pair ofdiametrically opposed, downwardly opening radial grooves 100 extendingfrom recess 99 partially outwardly to the outer periphery of rotor 68. Afilter screen 101, held against a shoulder 102 of bore 98 by a splitring 193, filters the lubricating oil passing upwardly through bore 98to recess 99 and grooves 100. As rotor 68 rotate at a substantial speed,the lubricating oil is thrown out through grooves 100 under rotor 68 andinto annular space 71 Where it is entrained with the refrigerant gas andpasses therewith from chamber 61 through holes 74. The oil so carriedwith the refrigerant gas removes a substantial amount of heat from themotor-compressor to the precooler 14. The entrained oil is cooled alongwith the compressed refrigerant gas in pre-cooler 14 and is re turned tothe motor-compressor through passage 94 to provide improved cooling ofthe motor'compressor. It has been found that such use of the lubricatingoil to augment the pre-cooled refrigerant cooling of the motorcomprcssorsubstantially increases the total cooling effect obtainable, and thussubstantially increases the efficiency of operation of themotor-compressor.

Shaft 69 is further lubricated by lubricating oil passing upwardlythrough recess 99 and outwardly through a radial hole 104 at the upperend thereof into a spiral groove 105 in the periphery of the shaft 69which extends upwardly of hub 70 of the front head 34. Thus, thelubricating oil is urged upwardly through groove 105 by the centrifugalforce thereof, spills onto the top of hub 70, and flows downwardlytherefrom through a plurality of large openings 106 in the bottom of anannular upwardly extending flange 107 of front head 34.

As discussed briefly above. motor 15 is carried by cornpressor 16 sothat substantially the sole support of the motor-compressor combinationis by means of mounting plate 21. As best seen in FIGURES 1, 2, 4 and 5,motor 15 includes a stator 108 having four spaced holes 109 adjacent theperiphery thereof through which are passed bolts 110 threadedly engagingcorresponding threaded bores 111 in four enlargements 112 of front headflange 107. Each of enlargements 112 is rabbeted at its upper end 113 tocenter accurately the stator 108 relative to the axis of the compressor16. The armature 114 of motor 15 is press fitted to the upper end ofshaft 69. To assure a proper air gap between the armature and stator,holes 199 are preferably slightly larger in diameter than screws 110 sothat some slight adjustment of the positioning of the stator relative tothe armature may be made during the assembly of the motor-compressor.Further, to assure correct electrical positioning of the stator relativeto the compressor assembly, a suitable electro-sensing element (notshown) may be attached to shaft 69 prior to the mounting of the armaturethereon, and the compressor assembly rotated to determine the correctelectrical position of the stator. After this position has beendetermined, the armature 114 may be press fitted onto shaft 69accurately in the position determined.

Motor 15 may be a split phase induction type motor using a three-wireconnection for operation. The three motor leads 115, 116 and 117 areconnected respectively to terminals 118, 119 and 120 of a glass fusedterminal block 121 which extends through and is hermetically sealed tohousing upper member 19. As illustrated schematically in FIGURE 1,terminal 118 may be connected through a lead 122 to one side 123 of asuitable alternating current power supply. Terminals 119 and 120 may beconnected through leads 124 and 125 respectively to a starting relay 126having a thermoelectric heating element 127 controlling a switch 128.Thus, leads 124 and 125 are each energized when the compressor motor iscaused to start. When the motor reaches optimum operating speed, theheating element 127 causes switch 128 to break from contact 128a, whichde-energizes the start winding connected from lead 124. However, the runwinding remains energized through lead 125 and contact 1281). A singlepole, single throw switch 129 is in series with thermoelectric element127 to control the connection of starting relay 126 through a lead 130to the other side 131 of the power supply. Switch 129 may be of themanually operable or thermostatically controlled type as desired.

Summary 0] Operation Motor-compressor 10 comprises a rugged,hermetically sealed unit providing improved, trouble-free operation in aconventional household refrigerator. The motor-compressor receives lowpressure, gaseous refrigerant from the evaporator 11 of therefrigerator, compresses the gaseous refrigerant in the pump chamber 61by means of the eccentric notary pump 35, and passes the compressed,high pressure refrigerant together with entrained lubricating oilthrough an improved mufiiing structure to a pre-cooler 14 exteriorly ofthe motor-compressor. The pre-cooled, high pressure refrigerant gas,with the en trained lubricating oil, is then returned to themotor-compressor to discharge within housing 17 of the motor-compressoragainst the hub 70 comprising the means for journalling the rotor shaft69. This provides an improved cooling of the compressor substantiallyincreasing the efiiciency of operation thereof. The p re-cooled, highpressure refrigerant gas then flows around the motor 15 absorbing heatand exits from housing 17 through an outlet 48 in the upper portionthereof for delivery to a suitable condenser 12 wherein the refrigerantis liquefied and delivered to the evaporator in the conventional manner.

Motor 15 is carried by compressor 16 and compressor 16 is carried inhousing 17 solely by means of the mounting plate 21. Thus, assembly ofthe motor in the motor-compressor 10 is facilitated and a stable air gapbetween the armature 114 and stator 108 thereof is maintained even whenthe motor-compressor receives such rough treatment as being dropped. Byso mounting the motor on the compressor, the stator is precluded fromcompressor solely on the mounting plate 21 substantially precludestransmission of vibrations to without the motorcornpressor 10.

The improved motor-compressor design further provides for flexibility ofcapacity. Thus a substantial range of capacity, such as from one-ninthhorsepower up to onequarter horsepower, may be obtained merely bysuitable change of the diameter of the pump chamber 61 and thecorresponding motor capacity.

While we have shown and described one embodiment of the invention, it isto be understood that it is capable of many modifications. Changes,therefore, in the con struction and arrangement may be made without departing from the spirit and scope of the invention as defined in theappended claims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In a compressor apparatus, structure comprising: a housing having afirst inlet for passing inwardly evaporated refrigerant, a first outletfor delivering outwardly compressed refrigerant for precoo-ling thereof,a sewnd inlet for passing inwardly precooled refrigerant, and a secondoutlet for passing outwardly the precooled refrigerant; amotor-compressor in said housing and having a bearing; means forconducting evaporated refrigerant to said motor-compressor forcompression thereof; means for conducting the compressed refrigerantfrom the motorcompressor to said first outlet; and means for conductingthe precooled refrigerant firstly directly against said bearing to coolthe same and then around said motor-co-mpressor to said second outlet.

2. In a compressor apparatus, structure comprising: a housing having afirst inlet for passing inwardly evaporated refrigerant, a first outletfor delivering outwardly compressed refrigerant for precooling thereof,a second inlet for passing inwardly precooled refrigerant, and a secondoutlet for passing outwardly the recooled refrigerant; amotor-compressor in said housing and having a bearing with a boretherethrough; means for conducting evaporated refrigerant to saidmotor-compressor for compression thereof; means for conducting thecompressed refrigerant from the motor-compressor to said first outlet;and means for conducting the precooled refrigerant from said secondinlet firstly through said bo-re tocontact directly the bearing portiondefining said bore to cool the bearing and then around saidmotor-compressor to said second outlet.

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